Extended Wear Contact Lenses: an Alternative to Refractive Surgery

It is clear that extended wear is something that has vast potential for your practice. These lenses are fantastic devices that can make you and your practice look great in the eyes of your patients and possibly set you apart from your competitors.

To clearly see what is new we need to take a look back to see where EW lenses started. Conventional extended wear lenses have been around since 1984, but were largely unsuccessful. Hypoxia, allergic/toxic reactions and other factors initially caused unacceptable physiological responses. Manufacturers continued research and development of conventional designs that are worn for long periods of time, but planned replacement and disposable designs overtook conventional lenses. Many manufacturers continue to offer conventional designs for patients who either prefer this modality or have been successful in the past and don’t wish to change. Manufacturers that continue to offer conventional lenses include Ciba Vision, Coopervision, and Ocular Sciences.

Planned Replacement/Disposable Extended Wear

The primary lens designs currently utilized in practice for extended wear/flexible wear are planned replacement or disposable lenses. These lenses have provided the majority of the new EW fits for the last few years, and have continued to prove invaluable to the contact lens practitioner. Manufacturers and their lenses include:

1. Bausch and Lomb- Optima FW, Soflens O3/O4

2. Ciba Vision- Focus 1-2 Week, Fresh Look Series, Precision UV, Focus

3. Cooper Vision- Frequency 55, Preference Planned Replacement

4. Hydrogel Vision- Extreme H2O

5. Ocular Sciences- Hydrogenics 60UV, Hydron Biomedics,

6. Sunsoft- Multiples

7. Vistakon- Acuvue, Acuvue 2, Acuvue Toric

Silocon Hydrogels

In this writer’s opinion, the most exciting new advancement in contact lenses that can be worn in an EW mode in recent memory is the advent of silocon hydrogels. These devices have allowed for much safer extended wear and less contact lens-related complications. For purposes of this article, I am discussing them in a separate category. Ciba Vision Focus Day and Night is a monthly replacement disposable soft contact lens made from lotrafilcon A (a flurosilicon/hydrogel material) with a Dk/t of 175, a water content of 26% and can be worn for daily, weekly or monthly cycles. It is FDA approved for up to 30 days of extended wear. This product is currently available in the United States and is quickly becoming a mainstay in many offices. From the author’s personal experience it is a great lens that handles well, is comfortable on-eye and patients generally like it.

Gas Permeables

Often over-looked are Gas Permeable (formerly Rigid GPs….) lenses designed for Extended Wear use. It is my belief that as Orthokeratology/Corneal Refractive Therapy gains in favor in the professions, we will be paying more attention to these designs and materials. Manufacturers that currently offer materials that are approved for EW can be found at http://www.rgpli.org/materials.htm. This link will direct you to the Rigid Gas Permeable Lens Institute’s list, which is current and up-to-date. Key to the issue of GP is the transmissibility or Dk/t. This equation designates the important factors to remember in designing a custom Gas Permeable lens for EW use. This article is addressing materials versus trade names for specific designs because most Gas Perms are customized. The power (D), the material constant (k), and the thickness determine just how much oxygen passes through the lens. Either the Fatt or ANSI/ISO methods are utilized to determine DK/t and will provide a guide for the practitioner to use in determining appropriate materials. The “Big 2”, Polymer Technologies (a division of Bausch and Lomb), and Paragon Vision Sciences have their respective materials. Paragon offers the HDS 100 and the older Fluoroperm 92 and 151. Polymer has the EO, XO and the Equalens. Several other manufacturers have materials as well, including GT Labs Fluorex 500 and 700, and Menicon’s Menicon Z. Most of these materials are approved for up to 7 days of continuous wear. Menicon Z is the only Gas Permeable material approved for up to 30 days. When considering extended wear for an option, don’t leave out Gas Permeable lenses in the process….they can be the best lens available physiologically.

Benefits of Extended Wear

The recognized benefits of Extended Wear lens modalities are many. The idea of being able to place a lens on the eye and not remove it for up to 30 days is an idea that every patient would embrace if they knew the lens to be safe. Earlier designs may not have been as we liked, but today the idea is one whose time is possible here. If we had to list benefits they would probably look something like this:

1. Convenient

2. Easy to wear

3. Less handling

4. Less trouble than daily removal products

5. Less cleaning involved…and on and on.

Some of the intrinsic values of extended wear that may not immediately come to mind include the fact that they can be an alternative to refractive surgery. If you cut on the cornea and it goes wrong, the damage is permanent. A contact lens, even one fit poorly, can be replaced or re-fit, or even discontinued. Extended wear can be used for patients with arthritis or other debilitating diseases that limit handling ability.

They can also be used as a practice builder for you, and set you apart from the competition as a specialty fitter. Extended Wear has come a long way, baby and these new lenses can do all I discussed here for you and you’re patients and even more.

Contraindications

Any time you place a material or device over the cornea, oxygen is depleted somewhat, and it is important that you provide the follow up necessary to care for EW patients. They will require additional visits and more chair time. A number of things can go wrong, most of which are due to hypoxia. Neo-vascularization, stippling, straie, are just a few that may be exacerbated with extended wear lenses in place. Make certain if you are going to fit extended wear lens designs that you do the follow-up, and if something is causing a problem, you’ll be able to pick it up quickly and make corrections. The complications for the newer designs are minimal if you simply provide appropriate after-care!

Conclusion

It is clear that extended wear is something that has vast potential for your practice. These new lenses are fantastic devices that can make you and your practice look great in the eyes of your patients and possibly set you apart from your competitors. Many (including this author) have been skeptical about extended wear designs, because we saw the early lenses fail quite dramatically. But these new lenses WORK and work well. Take the time to try them and I know your patients will enjoy the benefits of extended wear.


Warren G. McDonald, PhD

One Comment

  1. Have been toying with the idea. Looking for info. Great post :)

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